🎯 Objective
Allocate an Elastic IP (EIP) in AWS to provide a static public IP address that can be attached to an EC2 instance. Unlike normal public IPs, Elastic IPs do not change when the instance stops or restarts.
🌐 Types of IP Addresses in AWS
Private IP
Used for internal communication inside a VPC
Automatically assigned to every EC2 instance
Cannot be accessed from the internet
Does not change during the instance lifecycle
Example: 172.31.25.14
Used for:
Application communication
Database connections
Internal services
Public IP
Used to access EC2 instances from the internet
Automatically assigned when launching an instance (if enabled)
Changes when the instance stops and starts
Example: 3.91.124.55
Used for:
SSH access
Web servers
Public APIs
Elastic IP
A static public IPv4 address provided by AWS
Can be attached or moved between instances
Does not change even if the instance stops or restarts
Example: 54.210.22.11
Used for:
Production web servers
DNS mapping
High availability systems
🌐 What is an Elastic IP?
An Elastic IP is a static IPv4 address designed for dynamic cloud computing.
Benefits
Static public IP address
Can be reassigned between instances
Useful for production servers
Prevents IP changes when instance restarts
Example use cases
Web servers
Bastion hosts
Load balancers
DNS records pointing to servers
🛠️ Steps to Allocate Elastic IP (AWS Console)
1. Sign in to AWS
Go to the AWS Management Console: https://console.aws.amazon.com/
1. Navigate to EC2
Click Services
Search for EC2
Open EC2 Dashboard
1. Open Elastic IP section
Left sidebar: Network & Security → Elastic IPs
1. Allocate new Elastic IP
1. Click Allocate Elastic IP address
1. Keep default settings:
Network Border Group → Default region
IP Address Pool → Amazon pool
1. Click Allocate
🔗 Associate Elastic IP with an EC2 instance
1. Select the Elastic IP
1. Click Actions → Associate Elastic IP address
1. Choose:
Resource type → Instance
Instance → Select your EC2 instance
1. Click Associate
🔍 Verify
Go to EC2 → Instances.
Your instance should now show the Elastic IP as its public IP.
⚠️ Important notes
AWS charges for unused Elastic IPs
5 Elastic IPs per region by default
Release unused Elastic IPs to avoid extra cost
Elastic IPs are designed for production workloads